Speaker
Description
Hydrogen production through solar water splitting is a clean solution to the actual energy demand. It can be carried out in a photoelectrochemical cell where a photoelectrode absorbs sunlight producing electron-hole pairs, then the charge carriers are collected separately to oxidize oxygen and reduce hydrogen from water. Several materials have been proposed and tested as photoelectrodes, being n-type oxide semiconductors the most suitable as photoanodes and p-type oxide semiconductors as photocathodes. However, the development of solar water splitting is still a challenge due to its low experimental efficiency. Therefore, a fundamental understanding of the charge carrier dynamics in oxide semiconductors is mandatory to improve the current efficiency. In that sense, time-resolved soft X-ray absorption spectroscopy is a technique capable to track the dynamics of electrons and holes at the same time with element selectivity, oxidation- and spin-state specificity making it adequate to give new insights of ultrafast carrier dynamics occurring in oxide semiconductors.
The project aims to develop of a novel methodology to explore ultrafast charge carrier dynamics in oxide semiconductors by time-resolved soft X-ray absorption spectroscopy. The main goal is to locally explore the transient electronic structure of p-type (Cu$_{2}$O and CuO) and n-type (α-Fe$_{2}$O$_{3}$ and WO$_{3}$) semiconductor thin films following NIR and UV excitation by monitoring the change of X-ray absorption spectrum at specific atomic edges (M- and L-edges). Additionally, the role of dopants as Ti in modifying the dynamics in α-Fe$_{2}$O$_{3}$ will be explored.
